Early in 1989, under the direction of the Board of Regents, an ad hoc planning panel was convened to explore in-depth the proper role for the NLM in the rapidly changing field of electronic imaging. After much deliberation, the NLM Planning Panel on Electronic Image Libraries made the following recommendation: "NLM should undertake a first project building a digital image library of volumetric data representing a complete, normal adult male and female. This Visible Human Project will include digitized photographic images for cryosectioning, digital images derived from computerized tomography and digital magnetic resonance images of cadavers [1]."
The initial aim of the Visible Human Project is the acquisition of transverse CT, MRI and cryosection images of a representative male and female cadaver at an average of one millimeter intervals. The corresponding transverse sections in each of the three modalities are to be registered with one another. A contract for acquisition of these pixel-based data was awarded in August 1991 to the University f Colorado at Denver. Victor M. Spitzer, Ph.D. and David G. Whitlock, M.D., Ph.D. are the principal investigators.
The male data set consists of MRI, CT and anatomical images. Axial MRI images of the head and neck and longitudinal sections of the rest of the body were obtained at 4 mm intervals. The MRI images are 256 pixel by 256 pixel resolution. Each pixel has 12 bits of grey tone resolution. The CT data consists of axial CT scans of the entire body taken at 1 mm intervals at a resolution of 512 pixels by 512 pixels where each pixel is made up of 12 bits of grey tone. The axial anatomical images are 2048 pixels by 1216 pixels where each pixel is defined by 24 bits of color, about 7.5 megabytes. The anatomical cross-sections are also at 1 mm intervals and coincide with the CT axial images. There are 1871 cross-sections for each mode, CT and anatomy. The complete male data set is 15 gigabytes in size.
Sample full scale images are available via NLM's FTP site: (nlmpubs.nlm.nih.gov). Six full color anatomical images and an explanatory README file can be found on the FTP site in (visible/bitmaps/color24) as (*.raw). Please be careful as each of these images is over 7 megabytes in size. Ten CT scan images and an explanatory README file can be found in (visible/bitmaps/ct) as (*.fre) (5 images captured while the cadaver was fresh) and (*.fro) (5 images captured after the cadaver was frozen). Six MRI scan images and an explanatory README file can be found in (visible/bitmaps/mri) as (*.t1).
Scaled down versions of all of these image files can be found on NLM's FTP site in (visible/gifs) as (*.gif) and on the NLM Gopher, (gopher.nlm.nih.gov) in the Visible Human Project section. On the World Wide Web, (http://www.nlm.nih.gov/) the images can be found on the Research Projects page, in the Visible Human Project section, as (*.jpg).
A license agreement for use of Visible Human Project data sets is required. It can be retrieved from NLM's gopher site. The agreement will be found in the section entitled Visible Human Project as a text file and as a downloadable WordPerfect file. It is also available from NLM's FTP site. The agreement will be found in section "visible" as a WordPerfect file, (vhpagree.wp) or as a text file, (vhpagree.txt). Two original signed copies of the agreement is required as well as a statement which explains your intended use of the data set. Send both signed copies of the agreement and the "use" statement to NLM's Visible Human Project office. The agreement will be signed by NLM and one of the originals returned. Your account and password to the Visible Human Project Internet FTP site will also be returned as well as information on where you may purchase the data set on 8 mm Exabyte or 4 mm DAT tape. The data set is being distributed from the FTP site and on tape in a Z-compressed UNIX TAR format. There are 6 tapes of anatomical images corresponding to 6 body regions: head, thorax, abdomen, pelvis, thighs, and feet. A 7th tape contains all the MRI and CT images. Each tape costs $150 in the US, Canada and Mexico, $300 elsewhere. An 8th, "sample," tape which contains anatomical images from the entire body at 1 cm increments is also available. The set of 8 tapes costs $1,000 in the US, Canada and Mexico, $2,000 elsewhere.
The data set from the female cadaver will have the same characteristics as the male cadaver with one exception. The axial anatomical images will be obtained at 0.33 mm intervals instead of 1.0 mm intervals. This will result in over 5,000 anatomical images. The data set is expected to be about 40 gigabytes in size.
Distribution is anticipated during the fall of 1995. The spacing in the "Z" direction will be reduced to 0.33 mm in order to match the 0.33mm pixel spacing in the "XY" plane. This will enable developers who are interested in three-dimensional reconstructions to work with cubic voxels.
The larger, long-term goal of the Visible Human Project is to produce a system of knowledge structures which will transparently link visual knowledge forms to symbolic knowledge formats. Methods need to be developed to link image data to symbolic text-based data which is comprised of names, hierarchies, principles and theories. Standards do not currently exist for such linkages. Generalizable methods like the use of hypermedia where words can be used to find pictures, and pictures can be used as an index into relevant text, are being experimented with. Basic research is needed in the description and representation of structures, and the connection of structural-anatomical to functional-physiological knowledge. The goal is to make the print library and the image library a single, unified resource for medical information.
For additional information on the Visible Human Project please contact:
Internet: ackerman@lhc.nlm.nih.gov